Authorized Littelfuse Distributor
Littelfuse KLNR350 - KLNR/KLSR series RK1 fast-acting fuses were the earliest type of current-limiting fuse developed. Their single-element, silver link design enables them to provide fast-acting overload and short-circuit protection. When used to protect inductive loads such as motors, solenoids, and transformers, KLNR/KLSR series fuses must be greatly oversized to prevent opening the fuses on harmless inrush currents. In such applications, KLNR/KLSR series fuses may only provide short-circuit protection. We recommend using POWR-PRO™ LLNRK/LLSRK series RK1, dual-element, time-delay fuses in all new applications requiring the current-limiting ability of UL Class RK1 fast-acting fuses, or in existing applications where fast-acting RK1 or RK5 fuses have been opening on harmless system surges such as motor starting currents.

Littelfuse KLNR350 KLNR/KLSR series RK1 fast-acting fuses were the earliest type of current-limiting fuse…

Alternate Item Number: KLNR350.X

UPC: 079458280920


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Contact for Pricing

Call +1 (262) 252-1600 (toll-free 877-268-3700) or email [email protected] for pricing and availability.

Overview

The Littelfuse KLNR350, part of the KLNR/KLSR series, is a foundational RK1 fast-acting fuse designed for industrial overload and short-circuit protection. Its single-element, silver link construction provides rapid response to fault conditions, safeguarding critical electrical systems from damaging currents. This fuse is crucial for protecting power distribution systems, motor control circuits, and other industrial infrastructure. The KLNR/KLSR series fuses were among the earliest current-limiting fuses developed, offering essential protection against high-magnitude short-circuit currents. The KLNR350's silver link material ensures a quick reaction time when a fault occurs. It is important to note that when protecting inductive loads such as motors, solenoids, and transformers, the KLNR/KLSR series fuses, including the KLNR350, may require significant oversizing to prevent nuisance tripping from harmless inrush currents. In such applications, the primary protective function of the KLNR350 may be limited to short-circuit protection. For applications requiring more advanced protection, especially those involving inductive loads or where system surges are a concern, Littelfuse recommends their POWR-PRO™ LLNRK/LLSRK series. These dual-element, time-delay fuses offer superior current-limiting capabilities and the necessary time-delay to accommodate inrush currents. The LLNRK/LLSRK series is recommended for new applications requiring UL Class RK1 fast-acting fuses or for upgrading existing systems using RK1 or RK5 fuses that experience nuisance tripping from motor starting currents. The KLNR350 is manufactured in the US and is a trusted component from Littelfuse, a recognized leader in circuit protection. Understanding the application parameters of the KLNR350 is key to ensuring optimal system performance and safety. For enhanced protection and better handling of inrush currents, consider Littelfuse's advanced fuse series.
  • Fast-acting overload and short-circuit protection
  • Single-element, silver link design for rapid fault response
  • Current-limiting capability for industrial applications
  • Essential for protecting power distribution and motor control circuits
  • Trusted Littelfuse quality and reliability

Specifications

Amperage Rating
7 Amp
Amperage Rating
7 A
Application
Control Circuits & Inst Protection
Brand Name
Littelfuse
Special Features
Fast-Acting
Standard
Supplemental Protection
Sub Brand
POWR-GARD BLF Series
Type
UL Supplemental
Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount

GPM-SRR90

Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount
Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20

C331156

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20
Fuse Block 600VAC 600VDC Class CC 30A 3-Pole Pressure Plate with Reinforced Clip

30323R

Fuse Block 600VAC 600VDC Class CC 30A 3-Pole Pressure Plate with Reinforced Clip
9F61 Size B Clips 1.6in

9F61BWW460

9F61 Size B Clips 1.6in
POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

LCC5

POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

Frequently Asked Questions

What types of fuses does Littelfuse offer for industrial applications?

Littelfuse offers UL Class fuses, high-speed fuses, medium voltage fuses, 10 x 38 mm fuses, and solar fuses for industrial applications.

What are Littelfuse high-speed fuses used for?

High-speed fuses protect critical power semiconductor devices against short circuits in power conversion applications like inverters and variable-speed drives.

What do Littelfuse medium voltage fuses protect?

Medium voltage fuses protect transformers, potential transformers, feeders, and motor circuits.

What are the voltage and amperage ranges for 10 x 38 mm fuses?

10 x 38 mm fuses are available with ratings from 125 to 1000 volts and 1/10 to 30 amperes.

What is the maximum voltage for Littelfuse solar fuses and holders?

Littelfuse offers solar fuses and holders up to 1500 Vdc for photovoltaic applications.

What conditions do Littelfuse feeder protection relays guard against?

Feeder protection relays protect circuits from overcurrent, ground faults, phase loss, overload, and other detrimental conditions.

What is unique about the Littelfuse Industrial Shock-Block® GFCI?

It is the first permanently connected special-purpose GFCI that meets UL Standard 943C Class C and Class D for people protection in industrial facilities.

How do Littelfuse arc-flash protection relays enhance safety?

These relays detect developing arc-flash incidents and send a trip signal to interrupt power before significant damage occurs.

What types of protection do Littelfuse motor protection relays offer?

They offer voltage monitors, current monitors, and Bluetooth-enhanced overload relays for low and medium voltage applications.

What is the Littelfuse Techline service for?

The Techline provides technical experts to answer questions about fuse and relay products, including cross references, technical information, and application assistance.

Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.